This has been said before by folks more polished than myself, but I felt the need to elaborate.
When doing spellwork, lets say, for money, you need to give the spell some place to actually GET your money from. It's possible that a rich relation may die and leave you a bundle, but lets be honest, unless they are already in frail health, or prone to do things that might get them killed, and already have a deep and abiding care for your welfare, that is a doubtful path of manifestation.
More likely, you will get more busy at work. Yes, the job you already have. Because that is your most frequently traveled way to get money. These things travel the path of least resistance usually. There is also a point of maximum saturation. If you are already making as much money as you can from your job, then you've reached maximum saturation there. Unless you make some other change, you wont be plucking more fruit from that tree.
Likewise in a spell to attract a romantic partner, you have to leave your house, or check your dating service email, or follow up on that random call you get from an old friend. Or if you do a spell to help you be more patient, expect more people to push your buttons, so that you can get some practice at being patient.
A lot of failures at magic are failures at follow up. Mistakes in life skills, rather than spellwork. Your spellwork can be totally sound, but unless you are accostomed to performing miracles on the regular, you have to till the earthly soil down here, to open a way for that seed to sprout.
In spellwork you alter the subtile causes that make the material world. You need something to ground them, otherwise you wont get the most bang for your buck. Your results will be very subtile, and much of the energy will be lost manufacturing conditions for manifestation. It's like if you turn on a garden faucet and wait till the water pressure wears a hole in the ground to catch the water so you can get a drink. It's much easier to get a cup.
That's all I have for now, just trying to keep in the habit of posting.